1. Field of the Invention
The present invention relates to an apparatus, a mold, and a method for manufacturing a metal-ceramic composite member in which a ceramic and a metal are firmly joined together by a direct joining strength on an interface therebetween, and further relates to an electronic member formed by mounting electronic devices on the manufactured metal-ceramic composite member.
2. Description of the Related Art
Metal-ceramic composite members taking advantages of characteristics of ceramic such as chemical stability, high melting point, insulation performance, high hardness, and relatively high thermal conductivity and characteristics of metal such as high strength, high toughness, easy workability, and electrical conductivity are in wide use for automobiles, electronic equipment, and so on, and typical examples thereof are metal-ceramic composite substrates and packages for automobile turbocharger rotors and for mounting high-power electronic elements.
As methods for manufacturing the metal-ceramic composite members, adhesive bonding, plating, metallization, thermal spraying, internal chill, brazing, and a DBC method are well known in the art, and as for metal-ceramic composite substrates among the metal-ceramic composite members, most of them have recently been manufactured by the DBC method using alumina substrates and a metal active brazing method using aluminum nitride substrates in view of cost problem.
This applicant has proposed a method and an apparatus for directly joining aluminum as a metal member to a ceramic member, and a mold therefor (for example, refer to Patent documents 1 to 3).
(Patent document 1)
Japanese Patent Laid-open No. Hei 07-276035
(Patent document 2)
Japanese Patent Laid-open No Hei 11-226717
(Patent document 3)
Japanese Patent Laid-open No. 2002-76551
Recently, in accordance with the expansion of the market for metal-ceramic composite members, there has been an increasing demand for the supply of metal-ceramic composite members in various shapes at low cost. There are some cases, however, where the aforesaid proposals cannot always fully respond to such a demand.
For example, when a metal-ceramic composite member, which is shown in, for example, FIG. 4C, FIG. 7, or FIG. 9, being so structured that a plurality of ceramic substrates are joined onto a joining metal is to be produced through the use a vertical-type mold according to the prior art in which the ceramic substrates are placed vertically, the ceramic substrates are given considerable buoyancy due to a poured molten metal to become unstable. Consequently, the position and posture of the ceramic substrates in the mold fluctuate even with a slight shock accompanying the pouring of the molten metal and the movement of the mold, which has been an obstacle to the manufacture of a desired metal-ceramic composite member. It might be possible as a method for solving this problem to provide a jig in the vertical-type mold so as to prevent the fluctuation in the position and posture that is caused by the floating of the ceramic substrates, but this method had to be given up due to the complication of the internal structure of the mold, the possibility that materials constituting the jig may become new contaminating sources, and so on.